If you thought that rapid and potentially catastrophic climate change was all bad, think again. High in the Mackenzie Mountains in Canada, a treasure trove of ancient hunting tools is being revealed as warming temperatures melt patches of ice that have been in place for thousands of years.

Ice patches are accumulations of annual snow that, until recently, remained frozen all year. For millennia, caribou seeking relief from summer heat and insects have made their way to ice patches where they bed down until cooler temperatures prevail. Hunters noticed caribou were, in effect, marooned on these ice islands and took advantage.

In 1997, sheep hunters discovered a 4,300-year-old dart shaft in caribou dung that had become exposed as the ice receded. Scientists who investigated the site found layers of caribou dung buried between annual deposits of ice. They also discovered a repository of well-preserved artifacts.

The highest mountain in the range, Keele Peak, in 2005(photo credit: wikipedia)

Since that discovery, researchers have found 2400-year-old spear throwing tools, a 1000-year-old ground squirrel snare, and bows and arrows dating back 850 years. Biologists involved in the project are examining dung for plant remains, insect parts, pollen and caribou parasites. Others are studying DNA evidence to track the lineage and migration patterns of caribou.

"The implements are truly amazing. There are wooden arrows and dart shafts so fine you can't believe someone sat down with a stone and made them," says Tom Andrews, an archaeologist with the Prince of Wales Northern Heritage Centre in Yellowknife

Unfortunately, the team is in a race against time. Each summer, the patches continue to melt. In fact, two of the eight original patches have already disappeared.

"We realize that the ice patches are continuing to melt and we have an ethical obligation to collect these artifacts as they are exposed," says Andrews. If left on the ground, exposed artifacts would be trampled by caribou or dissolved by the acidic soils. "In a year or two the artifacts would be gone."